[FFmpeg-devel] [PATCH v2] avformat: introduce AVStreamGroup
James Almer
jamrial at gmail.com
Mon Oct 23 17:08:51 EEST 2023
Signed-off-by: James Almer <jamrial at gmail.com>
---
Changes since the first version:
- The union will now hold pointers to Group type specific structs
- The array of elements in the group is now of pointers to the streams
rather than index values.
- Simplified the helpers
- Changed field type for idx and id
- Added an AVDictionary to hold metadata
libavformat/avformat.c | 30 +++++++++
libavformat/avformat.h | 138 +++++++++++++++++++++++++++++++++++++++++
libavformat/internal.h | 33 ++++++++++
libavformat/options.c | 62 ++++++++++++++++++
4 files changed, 263 insertions(+)
diff --git a/libavformat/avformat.c b/libavformat/avformat.c
index 5b8bb7879e..99cda56c2f 100644
--- a/libavformat/avformat.c
+++ b/libavformat/avformat.c
@@ -80,6 +80,24 @@ FF_ENABLE_DEPRECATION_WARNINGS
av_freep(pst);
}
+void ff_free_stream_group(AVStreamGroup **pstg)
+{
+ AVStreamGroup *stg = *pstg;
+
+ if (!stg)
+ return;
+
+ av_freep(&stg->streams);
+ av_freep(&stg->priv_data);
+ switch (stg->type) {
+ // Structs in the union are freed here
+ default:
+ break;
+ }
+
+ av_freep(pstg);
+}
+
void ff_remove_stream(AVFormatContext *s, AVStream *st)
{
av_assert0(s->nb_streams>0);
@@ -88,6 +106,14 @@ void ff_remove_stream(AVFormatContext *s, AVStream *st)
ff_free_stream(&s->streams[ --s->nb_streams ]);
}
+void ff_remove_stream_group(AVFormatContext *s, AVStreamGroup *stg)
+{
+ av_assert0(s->nb_stream_groups > 0);
+ av_assert0(s->stream_groups[ s->nb_stream_groups - 1 ] == stg);
+
+ ff_free_stream_group(&s->stream_groups[ --s->nb_stream_groups ]);
+}
+
/* XXX: suppress the packet queue */
void ff_flush_packet_queue(AVFormatContext *s)
{
@@ -118,6 +144,9 @@ void avformat_free_context(AVFormatContext *s)
for (unsigned i = 0; i < s->nb_streams; i++)
ff_free_stream(&s->streams[i]);
+ for (unsigned i = 0; i < s->nb_stream_groups; i++)
+ ff_free_stream_group(&s->stream_groups[i]);
+ s->nb_stream_groups = 0;
s->nb_streams = 0;
for (unsigned i = 0; i < s->nb_programs; i++) {
@@ -138,6 +167,7 @@ void avformat_free_context(AVFormatContext *s)
av_dict_free(&si->id3v2_meta);
av_packet_free(&si->pkt);
av_packet_free(&si->parse_pkt);
+ av_freep(&s->stream_groups);
av_freep(&s->streams);
ff_flush_packet_queue(s);
av_freep(&s->url);
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 9e7eca007e..f045084c8d 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1018,6 +1018,77 @@ typedef struct AVStream {
int pts_wrap_bits;
} AVStream;
+enum AVStreamGroupParamsType {
+ AV_STREAM_GROUP_PARAMS_NONE,
+};
+
+typedef struct AVStreamGroup {
+ /**
+ * A class for @ref avoptions. Set on group creation.
+ */
+ const AVClass *av_class;
+
+ void *priv_data;
+
+ /**
+ * Group index in AVFormatContext.
+ */
+ unsigned int index;
+
+ /**
+ * Group-specific group ID.
+ *
+ * decoding: set by libavformat
+ * encoding: set by the user, replaced by libavformat if left unset
+ */
+ int64_t id;
+
+ /**
+ * Group-specific type
+ *
+ * decoding: set by libavformat on group creation
+ * encoding: set by the user on group creation
+ */
+ enum AVStreamGroupParamsType type;
+
+ /**
+ * Group-specific type parameters
+ */
+ union {
+ uintptr_t dummy; // Placeholder
+ } params;
+
+ /**
+ * Metadata that applies to the whole file.
+ *
+ * - demuxing: set by libavformat in avformat_open_input()
+ * - muxing: may be set by the caller before avformat_write_header()
+ *
+ * Freed by libavformat in avformat_free_context().
+ */
+ AVDictionary *metadata;
+
+ /**
+ * Number of elements in AVStreamGroup.streams.
+ *
+ * Set by avformat_stream_group_add_stream() must not be modified by any other code.
+ */
+ unsigned int nb_streams;
+
+ /**
+ * A list of streams in the group. New entries are created with
+ * avformat_stream_group_add_stream().
+ *
+ * - demuxing: entries are created by libavformat in avformat_open_input().
+ * If AVFMTCTX_NOHEADER is set in ctx_flags, then new entries may also
+ * appear in av_read_frame().
+ * - muxing: entries are created by the user before avformat_write_header().
+ *
+ * Freed by libavformat in avformat_free_context().
+ */
+ const AVStream **streams;
+} AVStreamGroup;
+
struct AVCodecParserContext *av_stream_get_parser(const AVStream *s);
#if FF_API_GET_END_PTS
@@ -1726,6 +1797,26 @@ typedef struct AVFormatContext {
* @return 0 on success, a negative AVERROR code on failure
*/
int (*io_close2)(struct AVFormatContext *s, AVIOContext *pb);
+
+ /**
+ * Number of elements in AVFormatContext.stream_groups.
+ *
+ * Set by avformat_stream_group_create(), must not be modified by any other code.
+ */
+ unsigned int nb_stream_groups;
+
+ /**
+ * A list of all stream groups in the file. New groups are created with
+ * avformat_stream_group_create(), and filled with avformat_stream_group_add_stream().
+ *
+ * - demuxing: groups may be created by libavformat in avformat_open_input().
+ * If AVFMTCTX_NOHEADER is set in ctx_flags, then new groups may also
+ * appear in av_read_frame().
+ * - muxing: groups may be created by the user before avformat_write_header().
+ *
+ * Freed by libavformat in avformat_free_context().
+ */
+ AVStreamGroup **stream_groups;
} AVFormatContext;
/**
@@ -1844,6 +1935,28 @@ const AVClass *avformat_get_class(void);
*/
const AVClass *av_stream_get_class(void);
+/**
+ * Add a new empty stream group to a media file.
+ *
+ * When demuxing, it may be called by the demuxer in read_header(). If the
+ * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
+ * be called in read_packet().
+ *
+ * When muxing, may be called by the user before avformat_write_header().
+ *
+ * User is required to call avformat_free_context() to clean up the allocation
+ * by avformat_stream_group_create().
+ *
+ * New streams can be added to the group with avformat_stream_group_add_stream().
+ *
+ * @param s media file handle
+ *
+ * @return newly created group or NULL on error.
+ * @see avformat_new_stream, avformat_stream_group_add_stream.
+ */
+AVStreamGroup *avformat_stream_group_create(AVFormatContext *s,
+ enum AVStreamGroupParamsType type);
+
/**
* Add a new stream to a media file.
*
@@ -1863,6 +1976,31 @@ const AVClass *av_stream_get_class(void);
*/
AVStream *avformat_new_stream(AVFormatContext *s, const struct AVCodec *c);
+/**
+ * Add an already allocated stream to a stream group.
+ *
+ * When demuxing, it may be called by the demuxer in read_header(). If the
+ * flag AVFMTCTX_NOHEADER is set in s.ctx_flags, then it may also
+ * be called in read_packet().
+ *
+ * When muxing, may be called by the user before avformat_write_header() after
+ * having allocated a new group with avformat_stream_group_create() and stream with
+ * avformat_new_stream().
+ *
+ * User is required to call avformat_free_context() to clean up the allocation
+ * by avformat_stream_group_add_stream().
+ *
+ * @param stg stream group belonging to a media file.
+ * @param st stream in the media file to add to the group.
+ *
+ * @retval 0 success
+ * @retval AVERROR(EEXIST) the stream was already in the group
+ * @retval "another negative error code" legitimate errors
+ *
+ * @see avformat_new_stream, avformat_stream_group_create.
+ */
+int avformat_stream_group_add_stream(AVStreamGroup *stg, const AVStream *st);
+
#if FF_API_AVSTREAM_SIDE_DATA
/**
* Wrap an existing array as stream side data.
diff --git a/libavformat/internal.h b/libavformat/internal.h
index 7702986c9c..c6181683ef 100644
--- a/libavformat/internal.h
+++ b/libavformat/internal.h
@@ -202,6 +202,7 @@ typedef struct FFStream {
*/
AVStream pub;
+ AVFormatContext *fmtctx;
/**
* Set to 1 if the codec allows reordering, so pts can be different
* from dts.
@@ -427,6 +428,26 @@ static av_always_inline const FFStream *cffstream(const AVStream *st)
return (const FFStream*)st;
}
+typedef struct FFStreamGroup {
+ /**
+ * The public context.
+ */
+ AVStreamGroup pub;
+
+ AVFormatContext *fmtctx;
+} FFStreamGroup;
+
+
+static av_always_inline FFStreamGroup *ffstreamgroup(AVStreamGroup *stg)
+{
+ return (FFStreamGroup*)stg;
+}
+
+static av_always_inline const FFStreamGroup *cffstreamgroup(const AVStreamGroup *stg)
+{
+ return (const FFStreamGroup*)stg;
+}
+
#ifdef __GNUC__
#define dynarray_add(tab, nb_ptr, elem)\
do {\
@@ -608,6 +629,18 @@ void ff_free_stream(AVStream **st);
*/
void ff_remove_stream(AVFormatContext *s, AVStream *st);
+/**
+ * Frees a stream group without modifying the corresponding AVFormatContext.
+ * Must only be called if the latter doesn't matter or if the stream
+ * is not yet attached to an AVFormatContext.
+ */
+void ff_free_stream_group(AVStreamGroup **pstg);
+/**
+ * Remove a stream group from its AVFormatContext and free it.
+ * The group must be the last stream of the AVFormatContext.
+ */
+void ff_remove_stream_group(AVFormatContext *s, AVStreamGroup *stg);
+
unsigned int ff_codec_get_tag(const AVCodecTag *tags, enum AVCodecID id);
enum AVCodecID ff_codec_get_id(const AVCodecTag *tags, unsigned int tag);
diff --git a/libavformat/options.c b/libavformat/options.c
index 0f79fe0fa4..09eb13e97a 100644
--- a/libavformat/options.c
+++ b/libavformat/options.c
@@ -270,6 +270,7 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
if (!st->codecpar)
goto fail;
+ sti->fmtctx = s;
sti->avctx = avcodec_alloc_context3(NULL);
if (!sti->avctx)
goto fail;
@@ -324,6 +325,67 @@ fail:
return NULL;
}
+AVStreamGroup *avformat_stream_group_create(AVFormatContext *s,
+ enum AVStreamGroupParamsType type)
+{
+ AVStreamGroup **stream_groups;
+ AVStreamGroup *stg;
+ FFStreamGroup *stgi;
+
+ stream_groups = av_realloc_array(s->stream_groups, s->nb_stream_groups + 1,
+ sizeof(*stream_groups));
+ if (!stream_groups)
+ return NULL;
+ s->stream_groups = stream_groups;
+
+ stgi = av_mallocz(sizeof(*stgi));
+ if (!stgi)
+ return NULL;
+ stg = &stgi->pub;
+
+ stg->type = type;
+ switch (type) {
+ // Structs in the union are allocated here
+ default:
+ break;
+ }
+
+ stgi->fmtctx = s;
+ stg->index = s->nb_stream_groups;
+
+ s->stream_groups[s->nb_stream_groups++] = stg;
+
+ return stg;
+}
+
+static int stream_group_add_stream(AVStreamGroup *stg, const AVStream *st)
+{
+ const AVStream **streams = av_realloc_array(stg->streams, stg->nb_streams + 1,
+ sizeof(*stg->streams));
+ if (!streams)
+ return AVERROR(ENOMEM);
+
+ stg->streams = streams;
+ stg->streams[stg->nb_streams++] = st;
+
+ return 0;
+}
+
+int avformat_stream_group_add_stream(AVStreamGroup *stg, const AVStream *st)
+{
+ const FFStreamGroup *stgi = cffstreamgroup(stg);
+ const FFStream *sti = cffstream(st);
+
+ if (stgi->fmtctx != sti->fmtctx)
+ return AVERROR(EINVAL);
+
+ for (int i = 0; i < stg->nb_streams; i++)
+ if (stg->streams[i]->index == st->index)
+ return AVERROR(EEXIST);
+
+ return stream_group_add_stream(stg, st);
+}
+
static int option_is_disposition(const AVOption *opt)
{
return opt->type == AV_OPT_TYPE_CONST &&
--
2.42.0
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